Unified ISSU: Enhanced mode

Devices with linecards installed can use a new ISSU option called enhanced mode. Enhanced mode eliminates packet loss during the unified ISSU process by running a second copy of the Junos software in standby mode ready to take over when software moves from an old image to a new one. Use the request system software in-service-upgrade package-name.tgz enhanced-mode command to use unified ISSU with enhanced mode, or the request system software validate in-service-upgrade package-name.tgz enhanced-mode command to verify that your device and target release are compatible with enhanced mode.